As is known, a foldable frame can be unfolded to provide a larger space, in order to accommodate more articles, and can be folded to a compact volume, so as to occupy less space for collection and handling. For example, CN100459904C shows a portable folding frame mechanism, comprising: a frame located on both sides of frame layer, wherein: at least two layers of frame are vertically arranged between the frame on both sides. The frame layer consists of two symmetrical frame plates connected together by way of split joint with hinge members. Hinge members of each upper frame and lower frame are connected at both ends by a connecting rod. Each layer of the frame is respectively hinged at both ends with the frame on both sides. The connecting rod is provided with a barrel connector consisting of a sleeve and support rods hinged on both sides of the sleeve. The sleeve of the sleeve connector is moveably covered on the connecting rod, and the support rod ends on both sides of the sleeve are hinged respectively with the frame on both sides. With the hinge joints composing the frame in each part, the frame can be easily folded to form a stable structure under the restriction/guidance of the connecting rod.
During handling, it is only necessary relatively to fold the back of the folding frame by gently lifting the frame with hands inserted into the handle hole in the central part of the top frame., and with the help of the hinge joint of two plates composing the folding frame, and driving both sides of the frame folding inwardly, thereby reducing its volume, and greatly facilitating storage and portability. This technology provides a concept of a folding frame, but the frame can only have opening on side face, thereby limiting the application of the frame. How to improve the weakness of the existing technology and design a frame with opening on side face and an open structure on top becomes an object of this invention.